insidious

adjective

Definition of insidiousnext
as in treacherous
formal causing harm in a way that is gradual or not easily noticed Most people with this insidious disease have no idea that they are infected. an insidious enemy

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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of insidious Speaking of pop music, while the new ad format is expected to have its critics, there’s a far more insidious change afoot in that Green and Pleasant Land. — Anthony Crupi, Sportico.com, 12 June 2026 But most of its failures are subtler, more insidious. — Katy Waldman, New Yorker, 10 June 2026 What makes this deal particularly insidious is the trade-off at its core. — Joe Wilkins, Futurism, 10 June 2026 Best known for comedy series like Community (2009-15) and GLOW (2017-19), Alison Brie is taking on the role of Evil-Lyn, an insidious enchantress who serves as Skeletor’s main accomplice. — Keith Langston, PEOPLE, 6 June 2026 See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
  1. treacherous
  2. subtle
  3. false
  4. deceptive
  5. perfidious
  6. incorrect
  7. wrong
Adjective
  • The infamous cyclops briefly appeared, as well as footage of Odysseus and his men battling the cannibalistic race of giants known as Laestrygonians and navigating around the treacherous whirlpool Charybdis.
    — Jennifer Ouellette, ArsTechnica, 1 July 2026
  • According to the hiking blog, The Hiking HI, the rock bridge can only be traversed at low tide, but can be treacherous either way.
    — Sam Gillette, PEOPLE, 30 June 2026
Definition of treacherous
Adjective
  • Obviously there’s a resemblance but in a really subtle and tasteful way.
    — Reece Andavolgyi, InStyle, 4 July 2026
  • Your reward will be the sight of a tiny pale point with a subtle blue-green tint.
    — Jamie Carter, Space.com, 3 July 2026
Definition of subtle
Adjective
  • An infusion of false hope, however, is all the equalizer was.
    — Tom Krasovic, San Diego Union-Tribune, 8 July 2026
  • Her post received 22,000 likes, and Elon Musk—who regularly boosts white-supremacist perspectives—and Joe Rogan have made similar claims about the group being a false-flag operation.
    — Ali Breland, The Atlantic, 8 July 2026
Definition of false
Adjective
  • The state agency said clinic staffers had clients sign a personal injury waiver, which the commission said was unenforceable, against public policy and deceptive and dishonest.
    — Ashley Hiruko, ProPublica, 8 July 2026
  • Bartůňková and Krejčíková share finesse in the front of the court as well as deceptive power, with Bartůňková’s excellent spot-serving giving her a platform and Krejčíková’s ability to change rhythm at will trying to destabilize it.
    — Ava Wallace, New York Times, 2 July 2026
Definition of deceptive
Adjective
  • This is perhaps the most perfidious practice of this sort of politics.
    — David M. Drucker, Twin Cities, 3 June 2026
  • Pakistan was a perfidious ‘ally’ in Afghanistan, backing the Taliban while pretending to be our friends.
    — Efrat Lachter, FOXNews.com, 18 Apr. 2026
Definition of perfidious
Adjective
  • In 2024, Air Canada's AI agent gave a passenger incorrect information about bereavement fares.
    — Stu Sjouwerman, Forbes.com, 7 July 2026
  • Even though talks with the Boston Red Sox at last year’s deadline never got close, the confusion provided by an incorrect tweet announcing Ryan’s trade to New England put the pitcher at the top of every trade list before the season even began.
    — Dan Hayes, New York Times, 6 July 2026
Definition of incorrect
Adjective
  • Critics, and even some supporters, said Soto-Martínez was making his move at the wrong time.
    — Melissa Gomez, Los Angeles Times, 4 July 2026
  • That could always be wrong, of course, but at least that’s the garage talk heading into the weekend.
    — Jess Bryant, New York Times, 4 July 2026
Definition of wrong

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inside tracks
insidious
insidiously
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Cite this Entry

“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 11 Jul. 2026.

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Nglish: Translation of insidious for Spanish Speakers

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